The present invention relates to a terminal equipment which performs disaster prevention under the control of a control panel, and a fire alarm system including the terminal equipment.
The present invention also relates to restriction of access to a memory in the terminal equipment.
Conventionally, a fire alarm system installed in a building or the like is configured mainly by a control panel which is disposed in a disaster prevention center or the like, and a plurality of terminal equipments such as fire detectors which are connected to the control panel via lines, and perform disaster prevention while exchanging predetermined command signals and data signals between the control panel and the terminal equipments by means of polling communication.
In such a fire alarm system, initialization of each of the terminal equipments is manually performed. In the case where the terminal equipment is a detector, for example, works of adjusting the sensitivity to a predetermined level depending on a detected object, i.e., smoke or heat, and, when the detector has a unique communication address, manually setting the address by using a dip switch must be conducted. In the control panel, furthermore, a work of matching the sensitivity level with each of the terminal equipments in accordance with the setting of the terminal equipments is required.
These works must be conducted not only in the initial start-up of the fire alarm system, but also in replacement of terminal equipments during maintenance or inspection. In a large fire alarm system in which several hundreds of terminal equipments are connected, an enormous amount of work must be conducted.
In such a fire alarm system, a nonvolatile memory may be disposed in each of terminal equipments, and various kinds of data such as the address and the sensitivity of the terminal equipment itself are stored in the memory. The provision of such a memory allows setting of various data to be easily performed by electrically rewriting the contents of the memory in a manufacturing stage of the terminal equipment or an installing stage of the fire alarm system. Therefore, it is not required to individually dispose a dip switch for setting an address, a circuit for adjusting the sensitivity, and the like, in terminal equipments.
Any person which is able to electrically access such a terminal equipment can perform rewriting or the like on a memory of the terminal equipment. Namely, not only a manufacturer who produces and manages the terminal equipment, but also a user who purchases the terminal equipment from the manufacturer and installs a fire alarm system, and an operator who operates the fire alarm system can access the terminal equipment. There is a possibility that various preset values in the memory may be freely changed by the user or the operator.
If the sensitivity of a detector and so on are freely changed by the operator or the like, there arises a probability that the fire alarm system itself cannot correctly act so that a false alarm and an alarm failure occur more frequently.
It is the first object of the invention to reduce the amount of work in start-up, maintenance, and inspection of a fire alarm system.
It is the second object of the invention to provide a fire alarm system of high reliability in which access to a memory disposed in a terminal equipment is restricted to prevent an inadequate change of settings and the like from occurring.
In order to achieve the above objects, according to the present invention, there is provided a terminal equipment, which is connected to a control panel and controlled by the control panel, comprising a memory, which stores characteristic data indicating characteristics of the terminal equipment.
In this configuration, a work of initializing the terminal equipment is substantially unnecessary when the terminal is installed into a fire alarm system, and when the terminal is replaced with another one, unlike the case where initialization is manually performed.
For example, the terminal equipments are various kinds of fire detectors, gas detectors, smoke control system, manual call points, local alarm bells, and the like. The characteristic data may include: product type of the terminal equipment, such as a detector or a smoke control system; type of element; and sensitivity (in the case of a detector); and a voltage level at which a smoke control system is activated (in the case of a smoke control system).
Preferably, the characteristic data is transmitted to the control panel. In this configuration, a work of initializing the terminal equipment in installation of a fire alarm system and replacement of the terminal equipment can be made substantially unnecessary, and the amount of work of initializing the control panel can be reduced.
The data may be transmitted from the terminal equipment to the control panel at the timing when the fire alarm system is activated. Each terminal equipment may be configured so as to transmit the characteristic data in response to a request signal from the control panel, or alternatively to transmit the characteristic data even when no request signal is sent from the control panel.
According to the invention, there is also provided a fire alarm system, comprising:
a plurality of terminal equipments;
a control panel, to which the terminal equipments are connected; and
a memory, provided with each terminal equipment, which stores characteristic data indicating characteristics of the associated terminal equipment,
wherein the control panel establishes an initial configuration of each terminal equipment based on the characteristic data transmitted from the respective terminal equipments.
In this configuration, a work of initializing the terminal equipment is substantially unnecessary when addition or attachment of the terminal equipment occurs in, for example, start-up of the fire alarm system, or replacement of the terminal equipment. Furthermore, also the work of initializing the control panel can be reduced.
Examples of the terminal equipments and the characteristic data are identical with those of the above. The predetermined are may be a single building, or a group consisting of plural buildings.
Preferably, the memory includes a non-volatile rewritable memory, and the characteristic data is stored in a predetermined address in the non-volatile rewritable memory. The characteristic data is transmitted to the control panel when the control panel requests the transmission while designating the predetermined address.
Here, it is preferable that the predetermined address is a common address to all the terminal equipments.
In the above configurations, the control panel instructs each terminal equipment to transmit the characteristic data with designating the address in place of the kind of data in the memory. When, in all the terminal equipments, a characteristic data is stored at the same address, the control panel is requested only to transmit the same instruction signal to all the terminal equipments, in order to collect characteristic data of the terminal equipments. Consequently, the process in the control panel can be simplified. When addresses of characteristic data in the terminal equipments, programs in the control panel and relating to initialization of the terminal equipments, and the physical structure (the number of wirings and the attachment portion) of a product are commonly set as described above among control panels and terminal equipments of different manufacturers, initialization between the control panel and each of the terminal equipments can be enabled simply by installing the terminal equipment in the same manner as so-called the plug and play.
Examples of the non-volatile rewritable memory are an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically EPROM), and a RAM (Random Access Memory) in which the power source is backed up.
Preferably, the control panel assigns an identification address to each terminal equipment to identify one terminal equipment from another.
Here, it is preferable that the control panel transmits a first address to the terminal equipments, prior to the assignment of the identification address. Each terminal equipment is provided with an initial address and a comparator which compares the initial address and the first address. Each terminal equipment rewrites the initial address into the assigned identification address when the comparator judges that the first address is coincident with the initial address.
In the above configurations, since the master receives can automatically assigns the identification addresses to the respective terminal equipments, it is possible to remarkably reduce the amount of work of initialization, unlike a case in which an address is manually set by using a dip switch.
According to the invention, there is also provided an access restricting method in a fire alarm system, comprising the steps of:
connecting a plurality of terminal equipments to a control panel, each terminal equipment including a memory;
assigning a level indicating access allowability from the control panel, to the memory in each terminal equipment; and
providing a prohibition in the memory in each terminal equipment in accordance with the assigned access allowability level.
In this configuration, since the level is set according to relationships between the terminal equipment and the control panel, therefore, it is possible to prevent inadequate rewriting of data from occurring to attain a reliable fire alarm system.
Preferably, the prohibition providing step includes a step of determining a prohibited command transmitted from the control panel in accordance with the access allowability level.
Alternatively, the prohibition providing step includes a step of determining data which is writable by the control panel onto the memory, in accordance with the access allowability level.
In the above configurations, unauthorized access or rewriting by the control panel is prevented from occurring.
Here, it is preferable that the method further comprises the step of dividing the memory into a plurality of areas. The prohibition providing step includes a step of determining at least one area which stores the writable data, in accordance with the access allowability level.
Here, it is preferable that the level assigning step includes a step of writing data indicating the access allowability onto an area of exclusive use in the divided areas.
Here, it is preferable that the writing of the access allowability data is permitted for once. In this configuration, the level can be never rewritten so that unauthorized access or unauthorized rewriting can be certainly prevented from occurring.
Preferably, the access restriction is invalidated when a maintenance work for the terminal equipment is performed.
In this configuration, necessary access to or rewriting of data can be performed through the control panel or a maintenance device irrespective of the assigned level.
However, it does not mean that the control panel or the maintenance device can access the memory of each terminal equipment without any restriction.
In the specification, the term xe2x80x9cmaintenancexe2x80x9d includes maintenance, inspection, repair, replacement, etc.